Tie rivet for saw chain

ABSTRACT

Embodiments provide a tie rivet with a body that is configured to ride on a rail of a guide bar, and an integrated rivet extending from an inner surface of the body. The integrated rivet may include a draft angle that varies over a circumference of the integrated rivet. Additionally, or alternatively, the tie rivet may include an undercut portion around at least a portion of the integrated rivet. The undercut portion may be recessed from the inner surface of the body. Other embodiments may be described and claimed.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 62/110,328, filed Jan. 30, 2015, entitled “TIE RIVET FORSAW CHAIN,” the entire disclosure of which is hereby incorporated byreference.

TECHNICAL FIELD

Embodiments herein relate to the field of saw chains, and, morespecifically, to tie rivets for saw chains.

BACKGROUND

Saw chains for chainsaws typically include a plurality of links, such ascutter links, drive links, and tie straps, coupled to one another byrivets. The rivets are typically manufactured separately from the links,and the rivets can come loose during operation of the saw chain.Furthermore, for small saw chains, the small rivets and links can bedifficult to manipulate.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be readily understood by the following detaileddescription in conjunction with the accompanying drawings and theappended claims. Embodiments are illustrated by way of example and notby way of limitation in the figures of the accompanying drawings.

FIG. 1A illustrates a top view of a tie rivet in accordance with variousembodiments.

FIG. 1B illustrates a side view of the tie rivet of FIG. 1A inaccordance with various embodiments.

FIG. 1C illustrates a cross-sectional view of the tie rivet of FIG. 1Balong the line K-K shown in FIG. 1B, in accordance with variousembodiments.

FIG. 1D illustrates a cross-sectional view of the tie rivet of FIG. 1Balong the line L-L shown in FIG. 1B, in accordance with variousembodiments.

FIG. 1E is a perspective view of the tie rivet of FIG. 1A, in accordancewith various embodiments.

FIG. 2A illustrates a side view of a saw chain in accordance withvarious embodiments.

FIG. 2B illustrates a top view of the saw chain of FIG. 2A in accordancewith various embodiments.

FIG. 2C illustrates a front view of the saw chain of FIG. 2A inaccordance with various embodiments.

FIG. 2D illustrates a cross-sectional view of the saw chain of FIG. 2Aalong the line A-A shown in FIG. 2A, in accordance with variousembodiments.

FIG. 2E illustrates an expanded view of the portion marked B in FIG. 2D,in accordance with various embodiments.

FIG. 3 illustrates another cross-sectional view of the tie rivet of FIG.1B along the line K-K shown in FIG. 1B, in accordance with variousembodiments.

FIG. 4A illustrates another cross-sectional view of the saw chain ofFIG. 2A along the line A-A shown in FIG. 2A, in accordance with variousembodiments.

FIG. 4B illustrates an expanded view of the portion marked C in FIG. 4A.

FIG. 5A illustrates a side view of another tie rivet in accordance withvarious embodiments.

FIG. 5B illustrates a cross-sectional view of the tie rivet of FIG. 5Aalong the line A-A shown in FIG. 5A, in accordance with variousembodiments.

FIG. 5C illustrates a cross-sectional view of the tie rivet of FIG. 5Aalong the line B-B shown in FIG. 5A, in accordance with variousembodiments.

FIG. 6A illustrates a perspective view of another tie rivet inaccordance with various embodiments.

FIG. 6B illustrates a side view of the tie rivet of FIG. 6A, inaccordance with various embodiments.

FIG. 6C illustrates a cross-sectional view of the tie rivet of FIG. 6Balong the line C-C shown in FIG. 6B, in accordance with variousembodiments.

FIG. 6D illustrates a cross-sectional view of the tie rivet of FIG. 6Balong the line D-D shown in FIG. 6B, in accordance with variousembodiments.

FIG. 7A illustrates a perspective view of another tie rivet inaccordance with various embodiments.

FIG. 7B illustrates a side view of the tie rivet of FIG. 7A inaccordance with various embodiments.

FIG. 7C illustrates a bottom view of the tie rivet of FIG. 7A inaccordance with various embodiments.

FIG. 7D illustrates a cross-sectional view of the tie rivet of FIG. 7Balong the line E-E shown in FIG. 7B, in accordance with variousembodiments.

FIG. 7E illustrates a cross-sectional view of the tie rivet of FIG. 7Balong the line F-F shown in FIG. 7B, in accordance with variousembodiments.

FIG. 8A illustrates a perspective view of a cutter tie rivet inaccordance with various embodiments.

FIG. 8B illustrates a front view of the cutter tie rivet of FIG. 8A, inaccordance with various embodiments.

FIG. 8C illustrates a bottom view of the cutter tie rivet of FIG. 8A, inaccordance with various embodiments.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof, and in which are shownby way of illustration embodiments that may be practiced. It is to beunderstood that other embodiments may be utilized and structural orlogical changes may be made without departing from the scope. Therefore,the following detailed description is not to be taken in a limitingsense, and the scope of embodiments is defined by the appended claimsand their equivalents.

Various operations may be described as multiple discrete operations inturn, in a manner that may be helpful in understanding embodiments;however, the order of description should not be construed to imply thatthese operations are order dependent.

The description may use perspective-based descriptions such as up/down,back/front, and top/bottom. Such descriptions are merely used tofacilitate the discussion and are not intended to restrict theapplication of disclosed embodiments.

The terms “coupled” and “connected,” along with their derivatives, maybe used. It should be understood that these terms are not intended assynonyms for each other. Rather, in particular embodiments, “connected”may be used to indicate that two or more elements are in direct physicalor electrical contact with each other. “Coupled” may mean that two ormore elements are in direct physical or electrical contact. However,“coupled” may also mean that two or more elements are not in directcontact with each other, but yet still cooperate or interact with eachother.

For the purposes of the description, a phrase in the form “A/B” or inthe form “A and/or B” means (A), (B), or (A and B). For the purposes ofthe description, a phrase in the form “at least one of A, B, and C”means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).For the purposes of the description, a phrase in the form “(A)B” means(B) or (AB) that is, A is an optional element.

The description may use the terms “embodiment” or “embodiments,” whichmay each refer to one or more of the same or different embodiments.Furthermore, the terms “comprising,” “including,” “having,” and thelike, as used with respect to embodiments, are synonymous, and aregenerally intended as “open” terms (e.g., the term “including” should beinterpreted as “including but not limited to,” the term “having” shouldbe interpreted as “having at least,” the term “includes” should beinterpreted as “includes but is not limited to,” etc.).

With respect to the use of any plural and/or singular terms herein,those having skill in the art can translate from the plural to thesingular and/or from the singular to the plural as is appropriate to thecontext and/or application. The various singular/plural permutations maybe expressly set forth herein for sake of clarity.

Embodiments herein provide apparatuses, systems, and methods related toa tie rivet for a saw chain. Embodiments further provide a saw chainthat includes a plurality of links coupled to one another in a chain,including one or more tie rivets. The tie rivet may include a bodyportion (also referred to as tie strap portion) that has a lengthconfigured to couple adjacent links, such as drive links, of a saw chainto one another. The tie rivet may further include one or two rivets thatextend from the body of the tie strap. The rivets may be disposed inand/or engage with a rivet hole of a connecting link (e.g., a drivelink) to couple the connecting link to another link. In someembodiments, the rivets may further couple the tie rivet to an opposingtie strap on the other side of the connecting link.

In various embodiments, saw chain may be configured to be driven on aguide bar of a chain saw. The guide bar may extend from a body of thechain saw and may generally include a pair of elongate portions runningfrom a proximal end of the guide bar (closer to the body) to a distalend of the guide bar (further from the body). The elongate portions maybe straight or may have a slight curvature. In some embodiments, theelongate portions may include a pair of rails, with a groove disposedbetween the rails.

The guide bar may further include a sprocket at the proximal and/ordistal end to drive the saw chain around the ends of the guide bar. Forexample, the guide bar may include a drive sprocket at the proximal endof the guide bar and a nose sprocket at the distal end of the guide bar.The sprocket may include a spur with a plurality of pockets to engagerespective links of the saw chain. In some embodiments, the sprocket mayfurther include a pair of rims with outer edges that define rails. Thespur may be sandwiched between the pair of rims. Other embodiments ofthe sprocket may not include rims.

In various embodiments, the saw chain may include a plurality of linkscoupled to one another in a chain. For example, the saw chain mayinclude one or more cutter links, drive links, and/or tie straps. Thecutter links may include a sharpened cutting edge for cutting aworkpiece (e.g., wood). In some embodiments, the cutter links mayfurther include a depth gauge to control a depth of cut of the cutterlink. For example, the depth gauge may be disposed in front of thecutting element (e.g., in the direction of travel of the saw chain).

In various embodiments, the drive links may be center links configuredfor riding in the groove of the guide bar and/or to engage with one ormore sprockets of the guide bar. For example, the drive links mayinclude a tang that extends downward from a body of the drive link toride in the groove of the guide bar and/or engage a pocket of thesprocket.

Additionally, or alternatively, some embodiments may provide a saw chainincluding cutter links integrated into a drive link. Such a link may bereferred to as a cutter drive link. The cutter drive link may include abody with a tang extending downward from the body, and a cutting elementand depth gauge extending upward from the body. Some embodiments mayprovide a saw chain including a plurality of cutter drive links coupledto one another by tie rivets as described herein. In some embodiments,the saw chain may include only cutter drive links and tie straps, andsome or all of the tie straps may be tie rivets as described herein.

In other embodiments, the saw chain may include tie strap cutter links(e.g., a tie strap with an integrated cutting element and depth gauge).One or more of the tie strap cutter links may be a tie rivet asdescribed herein. Accordingly, the tie strap cutter links may includeone or more integrated rivets, a cutting element, and a depth gauge. Thetie strap cutter links may be coupled to an opposing tie strap andconnecting drive links. The opposing tie strap and connecting drivelinks may be non-cutting links.

As discussed above, the tie rivet may include a body and at least onerivet extending from the body. The body may include an outer surface andan inner surface. The outer surface may generally face away from aconnecting link to which the tie strap is coupled, and the inner surfacemay generally face the connecting link. The one or more rivets mayextend from the inner surface. In some embodiments, the body may besubstantially flat. For example, the outer surface and/or inner surfaceof the body may be substantially flat (e.g., planar). In someembodiments, the outer surface and inner surface may be substantiallyparallel to one another.

The tie rivet may ride on one of the rails of the guide bar. Forexample, the tie rivet may include a pair of foot portions on a bottomsurface of the body. The foot portions may contact the rail as the tierivet traverses the guide bar. The foot portions may be separated on thebottom surface of the body or may be included in a continuous portion ofthe bottom surface.

In some embodiments, the tie rivet may further include a second pair offoot portions on a top surface of the body. This may allow the tie rivetto be reversible.

In various embodiments, the integrated rivet of the tie rivet mayinclude a shoulder and a hub. The shoulder may be configured to bedisposed in a rivet hole of the connecting link (e.g., drive link). Thehub may be configured to be disposed in or engage with a rivet hole ofthe opposing tie strap. In various embodiments, the shoulder may providea gap between the opposing tie straps to provide clearance for theconnecting links between the tie straps. In some embodiments, a radiusof the shoulder may be greater than a radius of the hub (e.g., asmeasured from a common center line) to facilitate the gap. For example,the radius of the shoulder may be greater than a radius of the rivethole in the opposing tie strap.

In some embodiments, the rivet hole in the opposing tie strap may extendcompletely through the body of the opposing tie strap. Alternatively,the rivet hole may be defined by a depression in the body of theopposing tie strap that is recessed from the inner surface of the body.The hub of the tie rivet may engage with the rivet hole in the opposingtie strap to keep the tie rivet connected to the opposing tie strap.

For example, in some embodiments, a rivet head may be formed by spinningthe hub, such as by a spinning anvil. Alternatively, the rivet mayinclude a concavity in the end of the rivet that may be struck with animplement to spread the end of the rivet to form a rivet head. In otherembodiments, the rivet head may be a crushed head. In yet otherembodiments, the rivet head may be a flush head that has a same orsimilar radius to the hub. The flush head may be joined to the rivethole of the opposing tie strap, such as by resistance welding, laserwelding, ion-beam welding, or another non-mechanical joining process.

In various embodiments, the integrated rivet of the tie rivet mayinclude a variable draft angle along a circumference of the side surfaceof the tie rivet. The draft angle may refer to an angle of the sidesurface of the rivet with respect to a center line through the axialcenter of the rivet. The rivet may have a non-zero draft angle over atleast a portion of the surface of the tie rivet to facilitate removal ofthe tie rivet from a mold that is used to manufacture the tie rivet.

For example, the side surface of the rivet may have a draft angle with afirst value over a first portion of the circumference of the sidesurface, and may have a draft angle with a second value over a secondportion of the circumference of the side surface. The second value maybe greater than the first value. The side surface may further includetransition portions between the first portion and the second portion.The draft angle of the side surface may change from the first value tothe second value (e.g., substantially continuously) over the transitionportions. In one example, the first value may be about 0 degrees (e.g.,the side surface may be substantially parallel with the center line),and the second value may be about 1 to about 5 degrees (e.g., about 2degrees).

It will be apparent that other values of the draft angle may be providedin other embodiments. For example, in some embodiments, the first valueand the second value may both be non-zero. Alternatively, in someembodiments, the draft angle may continuously change over the entirecircumference of the side surface of the rivet, or over the entirecircumference apart from the first portion.

The first portion, second portion, and/or transition portions may coverany suitable portion of the circumference of the side surface. Forexample, in some embodiments, the first portion may cover about 90degrees to about 180 degrees (e.g., about 120 degrees) of thecircumference, the second portion may cover about 120 degrees to about240 degrees (e.g., about 180 degrees) of the circumference, and/or thetransition portions may individually cover about 15 degrees to about 45degrees (e.g., about 30 degrees) of the circumference.

In various embodiments, the first portion of the side surface (e.g.,with the lower draft angle) may be disposed in a contact region of therivet. The contact region may be a region of the side surface that issubjected to the greatest contact force with the connecting link. Forexample, in some embodiments, the contact region may be an inner regionof the rivet that faces the other rivet of the tie rivet (or the rivetof the opposing tie strap in embodiments in which the tie rivet includesa single integrated rivet). The lower draft angle (e.g., 0 draft angle)of the first portion may facilitate contact between the side surface ofthe rivet and the rivet hole of the connecting link. Additionally, thehigher draft angle of the second portion may facilitate manufacturing ofthe tie rivet. Furthermore, the tie rivet with variable draft angle asdescribed herein may allow the tie rivet to be manufactured with lesscostly (e.g., less strict) tolerances, with less expensive tools, and/orusing simpler induction heat treat coils than prior saw chain links.

In some embodiments, the integrated rivet of the tie rivet may include avariable draft angle over only a portion of the length of the sidesurface. For example, in some embodiments, the rivet may include avariable draft angle over all or a portion of the shoulder of the rivet,and may include a substantially constant draft angle over the hub of therivet.

Conventional rivets typically include a 0 draft angle over the entirecircumference of the shoulder of the rivet. This is required since theseparate rivet is not oriented with respect to the tie strap until thesaw chain is assembled. Additionally, the rivet may rotate with respectto the tie strap over time, e.g., if the mechanical interference betweenthe spun rivet hub and the rivet hole of the tie strap is insufficient.However, the integrated rivets of the tie rivet disclosed herein have afixed orientation with respect to the tie strap portion (body), whichallows the portions of the side surface having different draft angles tobe properly oriented.

FIGS. 1A-1E illustrate a tie rivet 100 in accordance with variousembodiments. FIG. 1A is a top view of the tie rivet 100, and FIG. 1B isa side view of the tie rivet 100. FIG. 1C shows a cross-sectional viewof the tie rivet 100 along the line K-K shown in FIG. 1B, and FIG. 1Dshows a cross-sectional view of the tie rivet 100 along the line L-Lshown in FIG. 1B. FIG. 1E is a perspective view of the tie rivet 100.

Tie rivet 100 includes a body 102 with an inner surface 104 and an outersurface 106. Tie rivet 100 further includes integrated rivets 108 thatextend from the inner surface 104. The integrated rivets 108 form aunitary piece with the body 102, as opposed to a separate tie strap andrivets. The integrated rivets 108 include a shoulder 110 and a hub 112.The shoulder 110 is disposed between the body 102 and the hub 112, andhas a diameter that is larger than a diameter of the hub 112.

As best seen in FIG. 1B, the circumference of the rivet 108 is dividedinto a first portion 114, a second portion 116, and transition portions118 a and 118 b disposed between the first portion 114 and the secondportion 116. As shown in FIG. 1C, over the first portion 114, thesurface of the shoulder 110 has a draft angle of 0 degrees with respectto an axial center line 120 disposed through the axial center of therivet 108. Additionally, as shown in FIG. 1D, over the second portion116, the surface of the shoulder 110 has a draft angle of 2 degrees withrespect to the center line 120. The draft angle may gradually increasefrom 0 degrees to 2 degrees over the transition portions 118 a-b.

The hub 112 is shown in FIG. 1B with a draft angle of 0 degrees over anentire circumference of the hub 112. In other embodiments, the hub 112may include a non-zero draft angle over all or a portion of thecircumference of the hub 112.

As shown in FIG. 1B, the first portion 114 may cover 120 degrees of thecircumference of the rivet 108, the second portion 116 may cover 180degrees of the circumference of the rivet 108, and the transitionportions 118 a and 118 b may each cover 30 degrees of the circumferenceof the rivet 108. The radial lengths of the first portion 114, secondportion 116, and transition portions 118 a-b, as well as the values ofthe draft angles of each portion, are presented as examples. It will beapparent that other radial lengths and/or draft angles of the firstportion 114, second portion 116, and/or transition portions 118 a-b maybe used in other embodiments.

As discussed above, the lower draft angle (e.g., 0 draft angle) of thefirst portion 114 may facilitate contact between the surface of theshoulder 110 and the rivet hole of the connecting link. Additionally,the higher draft angle (e.g., 2 degree draft angle) of the secondportion 116 may facilitate manufacturing of the tie rivet.

The first portion 114 of the rivet 108, with the 0 draft angle, may bedisposed in a contact region of the rivet 108. The contact region may bea region of the side surface of the rivet 108 that is subjected to thegreatest contact force with the connecting link. For example, as shownin FIG. 1B, the contact region may be an inner region of the rivet 108that faces the other rivet 108 of the tie rivet 100.

FIGS. 2A-2E illustrate a portion of a saw chain 200 that includes thetie rivet 100 in accordance with various embodiments. FIG. 2Aillustrates a side view of the saw chain 200, FIG. 2B illustrates a topview of the saw chain 200, and FIG. 2C illustrates a front view of thesaw chain 200. FIG. 2D illustrates a cross-sectional view of the sawchain 200 along the line A-A shown in FIG. 2A. FIG. 2E illustrates anexpanded view of the portion marked B in FIG. 2D.

The saw chain 200 includes two drive cutter links 202 coupled to oneanother by the tie rivet 100. The drive cutter links 202 include a body204 with a tang 206 that is configured to ride in a groove of a guidebar (not shown) between the rails of the guide bar. The drive cutterlinks 202 further include a pair of rivet holes 208 extending throughthe body 204. Additionally, the drive cutter links 202 include asharpened cutting edge 210 and a depth gauge 212 extending upward fromthe body 204.

The rivets 108 of the tie rivet 100 extend through respective rivetholes 208 of the drive cutter links 202 to couple the drive cutter links202 to one another. The rivet holes 208 are disposed around the shoulder110 of the rivets 108.

The saw chain 200 further includes an opposing tie strap 214 oppositethe tie rivet 100. As best seen in FIG. 2E, the tie strap 214 includes apair of rivet holes 216 to receive respective rivets 108 of the tierivet 100 (e.g., to receive the hubs 112 of the respective rivets 108).The rivet holes 216 are recessed from an inner surface 218 of a body 220of the tie strap 214, but do not extend all the way through the body220. In other embodiments, the rivet holes 216 may extend all the waythrough the body 220.

The rivet holes 216 have a diameter that is greater than the diameter ofthe hubs 112 of the rivets 108, but less than the diameter of theshoulders 110 of the rivets 108. The hubs 112 may engage with the rivetholes 216 to hold the connection between the tie rivet 100 and the tiestrap 214. For example, the hubs 112 may form an interference fit withthe rivet holes 216, or may be joined to the rivet holes 216 byresistance welding, laser welding, ion-beam welding, or anothernon-mechanical joining process.

As best seen in FIG. 2E, the shoulder 110 of the rivet 108 has a draftangle of 0 degrees on the first portion 114 of the shoulder 110 and hasa draft angle of 2 degrees on the second portion 116 of the shoulder110. The 0 degree draft angle on the first portion 114 of the shoulder110 may facilitate contact between the shoulder 110 and the rivet hole208 of the drive cutter link 202 in the first portion 114 of theshoulder 110. The increased draft angle on the second portion 116 of theshoulder 110 may facilitate manufacture of the tie rivet 100.

In various embodiments, in addition to or instead of a variable draftangle, the tie rivet described herein may have an undercut portiondisposed around all or part of the integrated rivets. The undercutportion may be defined by a region of the tie rivet which is recessedfrom the inner surface of the body (e.g., toward the outer surface ofthe body). In some embodiments, the undercut portion may be curved(e.g., radiused) to form a continuous curved surface between the innersurface of the body and the rivet.

The undercut portion may facilitate the fit between the connecting links(e.g., drive links) and the tie rivet. For example, the undercut portionmay provide clearance for the drive link (e.g., the edge of the rivethole of the drive link) to get closer to the inner surface of the tierivet. Additionally, or alternatively, the undercut portion may allow atighter fit between the rivet hole of the drive link and the rivet ofthe tie rivet (e.g., may allow the drive link to have rivet holes thathave a width that is closer to the width of the corresponding rivet ofthe tie rivet). Furthermore, the undercut portion may increase fatiguestrength of the tie rivet.

Accordingly, the undercut radius may allow the saw chain to have smallergaps between adjacent connecting links (e.g., drive links).Additionally, droopiness of the saw chain may be reduced by tighter fitsbetween the rivet holes of the connecting links and the rivets of thetie rivet.

In some embodiments, the tie rivet may include the undercut portion ononly a portion of the circumference of the rivet. For example, theundercut portion may be included in the contact region of the rivet. Asdiscussed above, the contact region may be the portion of thecircumference of the rivet that is subjected to the greatest contactforce with the connecting link. For example, in some embodiments, thecontact region may be an inner region of the rivet that faces the otherrivet of the tie rivet (or the rivet of the opposing tie strap inembodiments in which the tie rivet includes a single integrated rivet).

In some embodiments, the tie rivet may include an undercut portion in afirst portion of the circumference of the rivet, and may not include anundercut portion in a second portion of the circumference of the rivet.The tie rivet may further include transition portions between the firstand second portions over which a depth of the undercut portion graduallychanges from the depth of the undercut portion in the first portion tothe depth of the undercut portion (e.g., 0 depth) in the second portion.The first portion, second portion, and transition portions may or maynot correspond to the first portion, second portion, and transitionportions discussed above with respect to the variable draft angle.

In other embodiments, the tie rivet may include the undercut portionaround the entire circumference of the rivet.

Referring again to FIGS. 1A-1E, the tie rivet 100 includes undercutportions 130 disposed around the base of the rivets 108. FIG. 3illustrates another cross-sectional view of the tie rivet 100 along theline K-K shown in FIG. 1B. The undercut portion 130 is recessed from aninnermost portion of the inner surface 104. For example, as shown inFIG. 3, a depth of the undercut portion 130 is about 0.002 inches fromthe innermost portion of the inner surface 104. Other embodiments mayinclude another suitable depth of the undercut portion 130.

Additionally, the undercut portion 130 is curved to provide a continuoussmooth surface between the inner surface 104 and the rivet 108. Forexample, as shown in FIG. 3, a radius of the undercut portion 130 isabout 0.006 inches. Other embodiments may include another suitableradius of the undercut portion 130.

The undercut portion 130 may extend around the entire circumference ofthe rivets 108. In other embodiments, the tie rivet 100 may include anundercut portion with a first depth over the first portion 114 of thecircumference of the rivets 108, and the tie rivet 100 may not includean undercut portion over the second portion 116 of the circumference ofthe tie rivets 108. Additionally, the depth of the undercut portion maygradually decrease over the transition portions 118 a-b from the firstportion 114 to the second portion 116. Alternatively, the tie rivet 100may have a non-zero undercut portion in the second portion 116 with adepth that is less than the depth of the undercut portion 130 in thefirst portion 114.

FIG. 4A illustrates another cross-sectional view of the saw chain 200along the line A-A shown in FIG. 2A, similar to FIG. 2D. FIG. 4Billustrates an expanded view of the portion marked C in FIG. 4A.

As best seen in FIG. 4B, the undercut portion 130 of the tie rivet 100allows the drive cutter link 202 to be close (e.g., in contact with) theinner surface 104 of the tie rivet 100. Additionally, undercut portion130 may allow the rivet hole 208 of the drive cutter link 202 to have awidth that is relatively close to the width of the shoulder 110 of therivet 108, thereby facilitating the fit between the rivet 108 and therivet hole 208.

The tie rivet described herein may be manufactured using any suitablemanufacturing process. For example, in some embodiments, the tie rivetmay be formed using machining, casting, hot or cold forging, progressiveforming, powder metal injection, metal injection molding,three-dimensional (3D) additive manufacturing processes, laser weldingof the rivet to the tie strap body, or another forming process.

FIGS. 5A-5C illustrate a tie rivet 500 in accordance with variousembodiments. FIG. 5A illustrates a side view of the tie rivet 500. FIG.5B illustrates a cross-sectional view of the tie rivet 500 along theline A-A shown in FIG. 5A, and FIG. 5C illustrates a cross-sectionalview of the tie rivet 500 along the line B-B shown in FIG. 5A.

Tie rivet 500 includes a body 502 with an inner surface 504 and an outersurface 506. Tie rivet 500 further includes integrated rivets 508 thatextend from the inner surface 504. The integrated rivets 508 form aunitary piece with the body 502, as opposed to a separate tie strap andrivets. The integrated rivets 508 include a shoulder 510 and a hub 512.The shoulder 510 is disposed between the body 502 and the hub 512, andhas a diameter that is larger than a diameter of the hub 512.

The outer surface 506 includes a recession 540 in an area thatcorresponds to a location of the rivet 508. The outer surface 506further includes a draft angle that slopes down away from the recession540.

Additionally, the inner surface 504 includes a draft angle that slopesaway from the rivets 508. The recession 540 and/or draft angles of theouter surface 506 and/or inner surface 504 may facilitate manufacture ofthe tie rivet 500.

FIGS. 6A-6D illustrate another tie rivet 600 in accordance with variousembodiments. FIG. 6A illustrates a perspective view of the tie rivet600, and FIG. 6B illustrates a side view of the tie rivet 600. FIG. 6Cillustrates a cross-sectional view of the tie rivet 600 along the lineC-C shown in FIG. 6B, and FIG. 6D illustrates a cross-sectional view ofthe tie rivet 600 along the line D-D shown in FIG. 6B.

Tie rivet 600 includes a body 602 with an inner surface 604 and an outersurface 606. Tie rivet 600 further includes integrated rivets 608 thatextend from the inner surface 604. The integrated rivets 608 form aunitary piece with the body 602, as opposed to a separate tie strap andrivets. The integrated rivets 608 include a shoulder 610 and a hub 612.The shoulder 610 is disposed between the body 602 and the hub 612, andhas a diameter that is larger than a diameter of the hub 612.

The outer surface 606 includes a recession 640 in an area thatcorresponds to a location of the rivet 608. The outer surface 606further includes a draft angle that slopes down away from the recession640. The recession 640 and/or draft angle of the outer surface 606 mayfacilitate manufacture of the tie rivet 600.

FIGS. 7A-7E illustrate another tie rivet 700 in accordance with variousembodiments. FIG. 7A illustrates a perspective view of the tie rivet700, FIG. 7B illustrates a side view of the tie rivet 700, and FIG. 7Cillustrates a bottom view of the tie rivet 700. FIG. 7D illustrates across-sectional view of the tie rivet 700 along the line E-E shown inFIG. 7B, and FIG. 7E illustrates a cross-sectional view of the tie rivet700 along the line F-F shown in FIG. 7B.

Tie rivet 700 includes a body 702 with an inner surface 704 and an outersurface 706. Tie rivet 700 further includes integrated rivets 708 thatextend from the inner surface 704. The integrated rivets 708 form aunitary piece with the body 702, as opposed to a separate tie strap andrivets. The integrated rivets 708 include a shoulder 710 and a hub 712.The shoulder 710 is disposed between the body 702 and the hub 712, andhas a diameter that is larger than a diameter of the hub 712.

The outer surface 706 includes a recession 740 in an area thatcorresponds to a location of the rivet 708. Additionally, the shoulder710 of the rivet 708 includes a variable draft angle, with a 0 degreedraft angle over a first portion 714 of the circumference of the rivet708 and a non-zero draft angle over a second portion 716 of thecircumference of the rivet 708. Furthermore, the shoulder 710 has agreater radius over the first portion 714 than the second portion 716 ofthe circumference.

Although the tie rivets 100, 500, 600, and 700 are illustrated in theFigures as non-cutting tie rivets, it will be apparent that any of thetie rivets 100, 500, 600, and 700 may be cutter tie rivets in someembodiments. The cutter tie rivets may include a cutting edge and adepth gauge that extend up from the body of the cutting tie rivet.

For example, FIGS. 8A-8C illustrate a cutter tie rivet 800 in accordancewith various embodiments. FIG. 8A illustrates a perspective view of thetie rivet 800, FIG. 8B illustrates a front view of the tie rivet 800,and FIG. 8C illustrates a bottom view of the tie rivet 800.

Cutter tie rivet 800 includes a body 802 with an inner surface 804 andan outer surface 806. Tie rivet 800 further includes integrated rivets808 that extend from the inner surface 804. The integrated rivets 808form a unitary piece with the body 802, as opposed to a separate tiestrap and rivets. The integrated rivets 808 include a shoulder 810 and ahub 812. The shoulder 810 is disposed between the body 802 and the hub812, and has a diameter that is larger than a diameter of the hub 812.The cutter tie rivet 800 further includes a cutting element 814 and adepth gauge 816 that extend up from the body 802.

In accordance with various embodiments, the shoulders 810 of the rivets808 include a variable draft angle. For example, the shoulders 810 areshown in FIGS. 8A-8C with a 0 degree draft angle over a first portion818 of the circumference of the rivet 808 and a non-zero draft angleover a second portion 820 of the circumference of the rivet 808.Transition portions 822 are disposed between the first portion 818 andsecond portion 820 and have a draft angle that transitions from the 0degree draft angle of the first portion 818 to the non-zero draft angleof the second portion 820.

Although certain embodiments have been illustrated and described herein,it will be appreciated by those of ordinary skill in the art that a widevariety of alternate and/or equivalent embodiments or implementationscalculated to achieve the same purposes may be substituted for theembodiments shown and described without departing from the scope. Thosewith skill in the art will readily appreciate that embodiments may beimplemented in a very wide variety of ways. This application is intendedto cover any adaptations or variations of the embodiments discussedherein. Therefore, it is manifestly intended that embodiments be limitedonly by the claims and the equivalents thereof.

What is claimed is:
 1. A tie rivet, comprising: a body having an inner surface and an outer surface; and an integrated rivet extending from the inner surface of the body, wherein the integrated rivet includes a shoulder configured to engage a rivet hole of a connecting link, wherein a side surface of the shoulder of the integrated rivet includes a circumferential inner portion having only a first draft angle and a circumferential outer portion having only a second draft angle, wherein the second draft angle is greater than the first draft angle, wherein the circumferential inner portion is located along an inner region of the integrated rivet arranged to face another rivet of the tie rivet, an opposing tie strap, or an opposing tie rivet and the circumferential outer portion is located along an outer region of the integrated rivet, wherein the first and second draft angles are measured as an angle between the side surface of the shoulder of the integrated rivet and a central longitudinal axis of the integrated rivet.
 2. The tie rivet of claim 1, wherein the integrated rivet further includes a hub.
 3. The tie rivet of claim 1, wherein the first draft angle is about 0 degrees.
 4. The tie rivet of claim 1, further comprising a transition portion between the circumferential inner portion and the circumferential outer portion, wherein the side surface of the integrated rivet includes a draft angle that varies from the first draft angle to the second draft angle along the transition portion.
 5. The tie rivet of claim 1, wherein the integrated rivet is a first integrated rivet, and wherein the tie rivet further includes a second integrated rivet extending from the inner surface of the body.
 6. The tie rivet of claim 1, wherein the outer surface includes a recession opposite the integrated rivet.
 7. The tie rivet of claim 1, wherein the second draft angle is about 1 to about 5 degrees.
 8. A saw chain including the tie rivet of claim 1, and further including a drive link having a rivet hole disposed around the integrated rivet of the tie rivet.
 9. The saw chain of claim 8, wherein the drive link is a drive cutter link having a sharpened cutting element and a tang. 